When all players have clear job definitions that are understood by all, the level of effort is clearly seen by all.
By talking to or teaching in small groups I believe the players will learn what the is expected from positions other than his own. This will make the team more competent and interchangeable too.
Just imagine the problems a Jr. has adapting when coming to the senior level half way through the season. New coach, new players, new systems, & a whole new way to play. The pressure & expectations to be successfull so that he can stay up are enormous.
With a Players Book it gives players the opportunity to get on the same page as everyone else quickly.